Open-end spinning devices of the indicated construction are known, for example, from German Patent Publication DE 36 36 182 A1.
With a spinning device of this type the rotor housing, which is open at its front, is closed in an airtight manner during the spinning process by a cover element fastened on a pivot housing of the spinning device. The cover element is screwed onto the pivot housing from the inside. In addition, a sliver opening device with a sliver drawing-in cylinder, an opening cylinder and a portion of a fiber guide conduit are arranged in the pivot housing. The rotating parts are arranged such that they are taken out of operation or slowed when the cover element of the spinning device is opened.
The cover element has a circular lip seal which rests against the rotor housing and seals it in an airtight manner during operation, i.e. when the pivot housing is pivoted closed and locked. In this case, an extension of the cover element extends into the rotating rotor and, among other things, contains the orifice of the fiber guide conduit. In this manner, the orifice of the fiber guide conduit is positioned sufficiently close to the fiber slide wall of the spinning rotor that the individual fibers delivered through the fiber conduit are correctly fed to the spinning rotor.
As can be seen, for example, in German Patent Publication DE 37 05 479 A1, the cover elements, which may also be identified as fiber conduit plates, have an exterior annular groove for a lip element as well as a central cover extension. Besides the orifice of the fiber guide conduit, a threaded bore is also formed in the cover extension for fastening a fiber draw-off nozzle. Although these cover elements have proven satisfactory in actual use, they are generally made in the form of injection molded parts and therefore are relatively expensive to produce.
Since these cover elements (or fiber conduit plates), particularly the cover extensions, must correspond to defined rotor diameters, it is necessary to also exchange the cover elements when an exchange of the spinning rotors becomes necessary, e.g., in the course of a change of a yarn batch.
Various attempts have been made in the past to increase the range of rotor sizes with which such cover elements may be employed or to simplify their structural design. However, the devices known so far have not succeeded in actual use.
For example, it is known from German Patent Publication GM 78 20 853 to employ an adapter which can be placed on the cover extension when needed. In this way it is intended to make it possible to maintain the required spinning geometries, in particular the distance between the orifice of the fiber guide conduit and the fiber slide wall surface of the rotor, even when a change to a larger spinning rotor is made.
Furthermore, it is known from German Patent Publication DE AS 21 30 582 to close the rotor housing by means of a cover element which has a centered recess for receiving a cylindrical, piston-like insertion element. This insertion element, which contains the orifice of a fiber guide conduit as well as a central yarn withdrawal conduit, is maintained inside this recess by a radially acting clamping screw. However, the structural design of this cylindrical insertion element is not suited to assure the dependable sealing of the rotor housing.